The use of hydraulic systems is pervasive in modern machinery. Hydraulic systems are an efficient means to transmit power through pressurized fluids to accomplish mechanical work. Though varied in design, many systems may utilize several common elements. In many applications, a main system supplies power to one or more subsystems, which are sometimes referred to as circuits. The basic components of a generalized hydraulic fluid power system may include a hydraulic fluid reservoir, a pump or compressor, transmitter lines, directional control valve(s), and an actuator. In addition, hydraulic systems may further be classified into open-center and closed-center systems.
A typical open-center hydraulic system may contain a hydraulic innervator control valve or a flow control valve that is “open” while in its center or neutral position allowing for hydraulic fluid or pump flow to pass through the valve and return to a reservoir. Open-center systems are customarily operated at relatively low pressures and may generally be used to operate a single actuator function or even movement. Such open-centered systems may exhibit reduced effectiveness when trying to operate several actuator functions/movements at once.
In a typical closed-center system, a flow control valve, when positioned in the center or neutral position, may be closed, stopping the flow of hydraulic fluid from an adjustable pump to an actuator. As a result, in a closed-center system, when a flow control valve is in a closed position, the adjustable pump may rest, reducing or stopping the flow of hydraulic fluid (or fluid) to, or from an adjustable pump. Closed-center systems customarily operate at relatively high pressures (as compared to open-center hydraulic systems) and generally may be configured to simultaneously and efficiently operate several actuator functions/movements.
A simple example demonstrates the difficulties of integrating both open-center and closed center hydraulic systems, and the long felt need within the industry of being able to simultaneously operate both systems using one adaptable hydraulic control system. For example, modern U.S. agricultural tractors are often configured with constant pressure hydraulic systems configured in the closed-center position, where a hydraulic innervator control valve allows the flow of fluid to an actuator when it is in the neutral position. On the other-hand, modern European tractors are often configured in an open-centered position, where a hydraulic innervator control valve allows for the pass-through of hydraulic fluid, or pump flow back to a reservoir in the neutral position. As a result of these two hydraulic operating systems, it may be impractical and prohibitively expensive to combine U.S. and European agricultural equipment due to this incompatibility.
Several approaches have been attempted to address this incompatibility between open-centered and closed-centered hydraulic systems. One approach has been to use multiple pumps to provide hydraulic fluid (or fluid) to a plurality of hydraulically controlled actuators, where for example one adjustable pump would, as one example, supply fluid to an low pressure, low flow volume open-center system, while another would provide fluid to a high pressure, high flow volume closed-center system. Such configurations often can be inefficient and prohibitively expensive. Others examples may include the use of complex switching of components, load sensing devices, manual switching of parts, variable pump controls, flow dividers, and/or any number of combinations of these elements.
Hydraulic systems have yet to practically address a self-contained hydraulic control system that may be compatible with, and adaptively integrate both high and low pressure, and variable volume flows, that are indicative of open-center and closed-center hydraulic systems, that do not require user modification, interaction or intervention.
Certain embodiments of the current inventive technology may involve a hydraulic control system that may operate with, or as an open-center or closed-center hydraulic system. Embodiments of the current adaptable hydraulic control system may be applied and expanded into numerous practical embodiments. For example, the current adaptable hydraulic control system may include numerous embodiments for various agricultural, mechanical, and/or industrial applications and the like, as can be readily appreciated by those skilled in the art. In the current application one exemplary embodiment, namely a hydraulic hay baler accumulator having a plurality of components that are hydraulically controlled is described for illustration purposes only and not should be seen as limiting the current inventive technology as such.